The present invention relates to a solar battery system in which electric energy generated by a solar battery is stored in a storage battery, and the stored electric energy is supplied to a load.
In a conventional solar battery system, a solar battery is installed at an angle of 45 to the ground in a southerly facing direction. Generally, such conventional solar battery systems comprise a storage battery, wherein the electrical output of the solar battery produced from the average duration of sunshine per one day obtained from meteorological observation data in Japan (usually about three hours) is stored in the storage battery, and the stored electric energy is used as the power source.
In such a system, during rainy or cloudy weather, the output of the solar battery is so weak that sufficient charging of the storage battery is impossible. Hence, such a conventional solar battery system is inoperable during rainy or cloudy weather. Therefore, in order to compensate for poor weather (referred to herein as xe2x80x9cunsunniness compensationxe2x80x9d) the capacity of a storage battery is increased, and in rainy or cloudy weather, stored electric energy is used as the power source. In such case, for example, if poor weather persists for 5 to 30 days, the capacity of the storage battery must be 5 to 30 times that of the needed daily electric power.
Such a conventional solar battery system, as described above, has been used for a long time. However, as the effective use of a conventional solar battery system at locations where power sources do not exist becomes popular, weather/environmental conditions which limit the use of solar battery systems become important factors to consider, since they pose basic problems that limit the installation of a solar battery system. For example, prior to installation many factors must be considered, such as the placement of the solar battery in a sunny location at an angle of 45xc2x0 to the ground facing south, installation of a solar battery in a location that does not mar the view, and that charge and discharge operation trouble is caused by snow lying on the surface of a solar battery.
That a solar battery system is convenient and safe are important conditions in the design of same, for the spread of use of such systems. However, speaking of conditions of design, it goes without saying that a new solar battery system is desired in which the charge and discharge operation is assured even in such cases where the solar battery is placed in the shade, and/or in rainy or cloudy weather, and conditions on the installation of a solar battery outside do not matter, such as installation of a solar battery perpendicular to the ground in snowy areas.
Accordingly, a solar battery system is disclosed, for example, in Japanese patent laying-open No. 177683 of 1995 (Heisei 7), which includes a combination of an electric double layer condenser as a storage battery and a large capacity solar battery which generates a given output even under weak solar light, in the shade, in rainy weather, etc. The solar battery system can be used for long periods of time even if chargings are repeated every day regardless of weather, since the number of charging and discharging cycles of the electric double layer condenser is in the hundreds of thousands. Further, since charging is possible even in the shade and in rainy weather, the installation location of the solar battery is irrelevant. Thus, the solar battery system may be made small and inexpensive.
However, the ratio of power output of a solar battery system placed in an ideal location facing the south versus a solar battery system placed in the shade in rainy weather is generally about {fraction (1/20)}. In the case of the above two examples, in order to generate sufficient needed daily electric energy, power output of the solar battery system placed in the shade in rainy weather must be about 8 times as large as the solar battery system placed in an ideal location facing south, necessitating a large and more expensive solar battery system.
With regards to theoretical values, assuming daily needed electrical power output is 10 Wh/day, the power output of the solar battery system in all ideal location facing the south=10 Wh/3h (the average duration of sunshine per day)=3 W, while power output of the solar battery system located in the shade in rainy weather={10 Wh/8h (charging time in the daytime)}xc3x9720 ((damping correction coefficient in the shade in rainy weather)=25 W. Accordingly, a solar battery system of large-size and large-output is needed.
Further, in a solar battery system which includes a combination of a storage battery having the capacity to store the daily required electric energy and a solar battery capable of charging the storage battery even in the shade in rainy weather, the operation of the solar battery system in all weather conditions is assured. However, although the solar battery system is placed in a location facing south and is large-sized, the storage battery is quickly charged with a sufficient daily electric energy, after charging, surplus output of the solar battery remains and is released as useless energy. Therefore, such a solar battery system is inefficient and uneconomical.
Even if the capacity of the storage battery is increased to avoid the wasteful release of valuable charged energy, the output of discharged electricity is constant, which ensures charge and discharge in case of the poor weather conditions. Even if weather or installation location of the solar battery is changed, the output of discharged power is constant and cannot be increased. As a result, such a solar battery system is uneconomical and performs only simple function.
Moreover, although a conventional solar battery system has an effective face, the conventional battery system needs a wide area for the installation thereof, is large-sized and high-priced, therefore uneconomical. Further, conventional solar battery systems are designed to deliver simply a constant supply of electric power determined by the load needed to be affected, and provide merely an intermittent constant level of electric power. The output of the solar battery system, the charging state of the storage battery, the quantity of electric power needed based on load and the control of charge and discharge, were not necessarily performed and/or considered.
The present invention is provided in consideration of the above-mentioned problems, and provides that although the quantity of power charged to a storage battery changes according to the output of a solar battery, which itself depends on the state of solar radiation at the location of the installation of the solar battery, the output discharge quantity is automatically controlled in accordance with the changing charge quantity, so that effective and wise control operation of charge and discharge, and efficient utilization of solar energy without waste, is possible.
Namely, the area occupied by the solar battery system to the number of solar battery panels is decreased, and the quantity of electric power needed in case of poor weather/environmental conditions is ensured. Further, when the solar battery system of the present invention is located in a sunny place facing the south, the present invention makes use of the valuable large quantity of power output generated by a large capacity solar battery, a large quantity of electric power is charged and stored into a storage battery, and the supply of a larger quantity of electric power into a load or loads can be automatically performed.
Further, it is another object of the present invention to provide a solar battery system which stores long-term data concerning charge and discharge in memory, so that the solar battery system has reliable data to ensure long-term, stable operation and reliable-maintaining function, and has a maintenance function based on such self-learning and self-diagnostic data stored into the memory, which can be used economically and without anxiety.
In order to attain the above-mentioned object, a solar battery system, as claimed in claim 1, is a solar battery system in which electric energy generated by a solar battery is stored in a storage battery and the stored electric energy may then be supplied to a load, wherein the solar battery system comprises a charge quantity detecting means for detecting the input charge quantity stored in the storage battery and a discharge quantity control means for controlling the output discharge quantity in accordance with data on the detected charge quantity obtained from the charge quantity detecting means.
In such solar battery system including a combination of solar battery and storage battery, output discharge quantity is controlled based on input charge quantity, needed electric energy is assured even in poor weather/environmental conditions, the solar battery system of the present invention, when installed in an ideal location, can make the best use of a large quantity of valuable output obtained from the large capacity solar battery, and a large quantity of electric energy is generated and stored in the storage battery so that the large supply of electric energy is made automatically available when needed. Accordingly, an economical and effective solar battery system can be realized.
A solar battery system as claimed in claim 2 is a solar battery system in which electric energy generated by a solar battery is stored in a storage battery, and the stored electric energy is supplied to a load, wherein the solar battery system comprises a charge quantity detecting means for detecting the charge quantity input into the storage battery, a discharge quantity detecting means for detecting the output discharge quantity, of electric energy charged into the storage battery, a storage means in which long-tern data on charge and discharge quantity of the storage battery detected by the charge quantity detecting means and the discharge quantity detecting means, and a discharge quantity control means for controlling the output discharge quantity in accordance with the data on charge and discharge quantity stored in the storage means.
In the above-mentioned embodiment, the solar battery can be operated stably and securely every day, over a long period of time. Further, more effective discharge quantity control can be achieved by accumulating data on charge and discharge quantity of the storage battery itself over a long period of time, by having the functions of self-learning and self-diagnostic, and by making efficient use of such functions to enable fine adjustment of the discharge quantity control means of the storage battery itself. Further, collected data on charge and discharge quantity can be used as valuable data for maintenance, quality control, and valuable area data, such as data on installation locations and weather factors for future development of solar energy products, as well as for utilization for obtaining higher reliability and good control.
A solar battery system as claimed in claim 3 is a solar battery system in which electric energy generated by a solar battery is stored in a storage battery, and the stored electric energy is supplied to a load, wherein the solar battery system comprises either a charge quantity detecting means for detecting the charge quantity input into the storage battery and a discharge quantity control means for controlling the output discharge quantity in accordance with the information on the detected charge quantity obtained from the charge quantity detecting means, or a charge quantity detecting means for detecting the charge quantity input into the storage battery, a discharge quantity detecting means for detecting the output discharge quantity, of electric energy stored in the storage battery, a storage means in which long-term data is stored on charge and discharge quantity of the storage battery detected by the charge quantity detecting means and the discharge quantity detecting means, and a discharge quantity control means for controlling the output discharge quantity in accordance with data on charge and discharge quantity stored in the storage means, and wherein the charge quantity detecting means is a charging voltage detecting means for detecting the charging voltage of the storage battery.
As a means for detecting charge and discharge electric energy, for example, an electric double layer condenser is used for the storage battery. Namely, electric energy of condenser is defined by the following equation:
Wxc2x7S=CV2/2
wherein W S is charge electric energy, C is electrostatic capacity, V is terminal voltage. The charged electric energy can be detected by determining the terminal voltage of the electric double layers condenser.
Example, if C=100 V, V=3 V, Wxc2x7S=CV2/2=450Wxc2x7sec=0.125 Wxc2x7h. Thus, 450 Watts of electric power can be charged and stored for a second, or 0.125 Watts of electric power can be charged and stored for one hour.
A solar battery system as claimed in claim 4 is a solar battery system in which electric energy generated by a solar battery is stored in a storage battery and the stored electric energy is supplied to a load, wherein the solar battery system comprises either a charge quantity detecting means for detecting the charge quantity input into the storage battery and a discharge quantity control means for controlling the discharge quantity output to a load in accordance with the information on the detected charge quantity obtained from the charge quantity detecting means, or a charge quantity detecting means for detecting the charge quantity input into the storage battery, a discharge quantity detecting means for detecting the output discharge quantity supplied to the load, of electric energy charged into the storage battery, a storage means in which long-term data on charge and discharge quantity of the storage battery detected by the charge quantity detecting means and the discharge quantity detecting means is stored, and a discharge quantity control means for controlling the output discharge quantity in accordance with data on charge and discharge quantity stored in the storage means, and wherein the charge quantity detecting means is a charging voltage detecting means for detecting the charging voltage of the storage battery, and the charge quantity detecting means is an accumulated charged electric energy detecting means for detecting the accumulated charged electric energy stored in the storage battery.
A solar battery system as claimed in claim 5 is a solar battery system in which electric energy generated by a solar battery is stored in a storage battery and the stored electric energy is supplied to a load, wherein the solar battery system comprises either a charge quantity detecting means for detecting the charge quantity input into the storage battery and a discharge quantity control means for controlling the output discharge quantity in accordance with the information on the detected charge quantity obtained from the charge quantity detecting means, or a charge quantity detecting means for detecting the charge quantity input into the storage battery, a discharge quantity detecting means for detecting the output discharge quantity of electric energy stored in the storage battery, a storage means in which long-term data on charge and discharge quantity of the storage battery detected by the charge quantity detecting means and the discharge quantity detecting means is stored, and a discharge quantity control means for controlling the output discharge quantity in accordance with data on charge and discharge quantity stored in the storage means, and wherein the charge quantity detecting means is a charging voltage detecting means for detecting the charging voltage of the storage battery, and the charge quantity detecting means is a monitoring condenser charging voltage detecting means for detecting the charging voltage of a monitoring condenser connected in parallel with the storage battery.
In such an embodiment, the charge quantity detecting means for detecting the charge quantity input into the storage battery can simply include means for detecting the accumulated charged electric energy stored in the storage battery or means for detecting the charging voltage of a monitoring condenser connected in parallel with the storage battery.
Further, by controlling the charge and discharge quantity in accordance with the charge quantity, control of the power supply by supplying the desired power corresponding to the load is made possible, wherein the needed quantity of power is assured even in poor weather/environment conditions. Further, where the solar battery is installed in an ideal location, best use is made of the large quantity of valuable power output obtained from the large capacity solar battery by storing a large quantity of electric energy in the storage battery and making same available at will. Accordingly, an economical and effective solar battery system can be realized.
A solar battery system as claimed in claim 6 is a solar battery system as claimed in any of claims 1 through 5, wherein the discharge quantity control means of the solar battery system controls the output discharge quantity by pulse width modulation control, time control, output voltage control or output current control of the power output to the load or loads.
Accordingly, an appropriate optional method may be selected from the group consisting of pulse width modulation control, time (intermittent) control, output voltage control or output current control of the output to the load or loads.
A solar battery system as claimed in claim 7 is a solar battery system in which electric energy generated by a solar battery is stored in a storage battery and the stored electric energy is supplied to a load or loads, wherein the solar battery system comprises a charge quantity detecting means for detecting the charge quantity input into the storage battery, a discharge quantity detecting means for detecting the output discharge quantity supplied to the load or loads, of electric energy stored in the storage battery, a storage means in which long-term data on charge and discharge quantity of the storage battery detected by the charge quantity detecting means and the discharge quantity detecting means is stored, a discharge quantity control means for controlling the output discharge quantity to the load or loads in accordance with data on charge and discharge quantity stored in the storage means, and an output means for outputting the information on maintenance or alarm in accordance with data on charge and discharge quantity stored in the storage means.
Accordingly, data of the present command signal of all sorts of control elements and long-term recording data on charge and discharge based on past operation are stored in order of time into the storage means, and outputted from the storage means to a display means or to an external device and displayed. Further, long-term data concerning operation, reliability and maintenance are obtained and become available for purposes of developing plans for future maintenance, the time of exchange, alarm and learning of the causes of poor operation and/or power generation.
A solar battery system as claimed in claim 8 is a solar battery system claimed in any of claims 1 through 7, wherein the solar battery is comprised of a plurality of solar battery panels disposed perpendicular to the surface of installation of the system.
Accordingly, since the solar battery is comprised of a plurality of solar battery panels disposed perpendicular to the surface of area of installation of the system, the space needed for installation of the solar battery panels to the number thereof is relatively small, the energy generated by the solar battery panels and charge quantity of the storage battery may still be assured, and the solar battery is more protected from damage by animal droppings, snow, and the like.
As mentioned above, since the solar battery system of the present invention includes a combination of solar battery and storage battery, and the output discharge quantity is controlled in accordance with charge quantity input into the storage battery, needed electric energy is assured even in poor weather/environmental conditions. Further, when the solar battery system of the above embodiment is installed in an ideal location (such as a sunny place facing south), best use is made of the large quantity of valuable output obtained from the large capacity solar battery, and the large quantity of electric energy is and stored in the storage battery so that the large supply of electric energy is available at will. Accordingly, an economical and effective solar battery system can be realized.
Further, data of the present command signal concerning all sorts of control elements is sent and long-term recording data on charge and discharge based on past operation is stored in order of time into the storage means, and is transferred from the storage means to a display means or to an external device and displayed. In addition, information concerning long-term operation, reliability and maintenance are obtained and stored in data memory so that such information on maintenance, the time of exchange, alarm and indication of bad causes can be accessed.
Further, since the solar battery is comprised of a plurality of solar battery panels disposed perpendicular to the surface of installation of the system, the space needed for installation of the solar battery panels to the number thereof is small, the energy generated by the solar battery panels and the charge quantity of the storage battery is assured, and the solar battery is protected from damage by animal droppings, snow and the like.